[mirror_frr.git] / pimd / mtracebis.c

/*
 * Multicast Traceroute for FRRouting
 * Copyright (C) 2018  Mladen Sablic
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifdef __linux__

#include "pim_igmp_mtrace.h"

#include "checksum.h"
#include "mtracebis_routeget.h"

#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <net/if.h>
#include <unistd.h>
#include <getopt.h>
#include <netdb.h>

#define MTRACEBIS_VERSION "0.1"
#define MTRACE_TIMEOUT (5)

#define IP_HDR_LEN (sizeof(struct ip))
#define IP_RA_LEN (4)
#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)

static const char *progname;
static void usage(void)
{
	fprintf(stderr, "Usage : %s <multicast source>\n", progname);
}
static void version(void)
{
	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
}

static void print_host(struct in_addr addr)
{
	struct hostent *h;

	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	if (h == NULL)
		printf("?");
	else
		printf("%s", h->h_name);
	printf(" (%s) ", inet_ntoa(addr));
}

static void print_line_no(int i)
{
	printf("%3d  ", -i);
}

static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
{
	static char buf[80];

	buf[0] = '\0';

	switch (proto) {
	case MTRACE_RTG_PROTO_DVMRP:
		return "DVMRP";
	case MTRACE_RTG_PROTO_MOSPF:
		return "MOSPF";
	case MTRACE_RTG_PROTO_PIM:
		return "PIM";
	case MTRACE_RTG_PROTO_CBT:
		return "CBT";
	case MTRACE_RTG_PROTO_PIM_SPECIAL:
		return "PIM special";
	case MTRACE_RTG_PROTO_PIM_STATIC:
		return "PIM static";
	case MTRACE_RTG_PROTO_DVMRP_STATIC:
		return "DVMRP static";
	case MTRACE_RTG_PROTO_PIM_MBGP:
		return "PIM MBGP";
	case MTRACE_RTG_PROTO_CBT_SPECIAL:
		return "CBT special";
	case MTRACE_RTG_PROTO_CBT_STATIC:
		return "CBT static";
	case MTRACE_RTG_PROTO_PIM_ASSERT:
		return "PIM assert";
	default:
		sprintf(buf, "unknown protocol (%d)", proto);
		return buf;
	}
}

static void print_rtg_proto(uint32_t rtg_proto)
{
	printf("%s", rtg_proto_str(rtg_proto));
}

static void print_fwd_ttl(uint32_t fwd_ttl)
{
	printf("thresh^ %d", fwd_ttl);
}

static const char *fwd_code_str(enum mtrace_fwd_code code)
{
	static char buf[80];

	buf[0] = '\0';

	switch (code) {
	case MTRACE_FWD_CODE_NO_ERROR:
		return "no error";
	case MTRACE_FWD_CODE_WRONG_IF:
		return "wrong interface";
	case MTRACE_FWD_CODE_PRUNE_SENT:
		return "prune sent";
	case MTRACE_FWD_CODE_PRUNE_RCVD:
		return "prune received";
	case MTRACE_FWD_CODE_SCOPED:
		return "scoped";
	case MTRACE_FWD_CODE_NO_ROUTE:
		return "no route";
	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
		return "wrong last hop";
	case MTRACE_FWD_CODE_NOT_FORWARDING:
		return "not forwarding";
	case MTRACE_FWD_CODE_REACHED_RP:
		return "reached RP";
	case MTRACE_FWD_CODE_RPF_IF:
		return "RPF interface";
	case MTRACE_FWD_CODE_NO_MULTICAST:
		return "no multicast";
	case MTRACE_FWD_CODE_INFO_HIDDEN:
		return "info hidden";
	case MTRACE_FWD_CODE_NO_SPACE:
		return "no space";
	case MTRACE_FWD_CODE_OLD_ROUTER:
		return "old router";
	case MTRACE_FWD_CODE_ADMIN_PROHIB:
		return "admin. prohib.";
	default:
		sprintf(buf, "unknown fwd. code (%d)", code);
		return buf;
	}
}

static void print_fwd_code(uint32_t fwd_code)
{
	printf("%s", fwd_code_str(fwd_code));
}

static void print_rsp(struct igmp_mtrace_rsp *rsp)
{
	print_host(rsp->outgoing);
	if (rsp->fwd_code == 0) {
		print_rtg_proto(rsp->rtg_proto);
		printf(" ");
		print_fwd_ttl(rsp->fwd_ttl);
	} else {
		print_fwd_code(rsp->fwd_code);
	}
	printf("\n");
}

static void print_dest(struct igmp_mtrace *mtrace)
{
	print_line_no(0);
	print_host(mtrace->dst_addr);
	printf("\n");
}

static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
{
	int i;
	int t = 0;

	for (i = 0; i < hops; i++)
		t += mtrace->rsp[i].fwd_ttl;

	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
}

static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
{
	int i;

	print_dest(mtrace);

	for (i = 0; i < hops; i++) {
		print_line_no(i + 1);
		print_rsp(&mtrace->rsp[i]);
	}
	print_summary(mtrace, hops, msec);
}

static int send_query(int fd, struct in_addr to_addr,
		      struct igmp_mtrace *mtrace)
{
	struct sockaddr_in to;
	socklen_t tolen;
	int sent;

	memset(&to, 0, sizeof(to));
	to.sin_family = AF_INET;
	to.sin_addr = to_addr;
	tolen = sizeof(to);

	sent = sendto(fd, (char *)mtrace, sizeof(*mtrace), MSG_DONTWAIT,
		      (struct sockaddr *)&to, tolen);

	if (sent < 1)
		return -1;
	return 0;
}

static void print_query(struct igmp_mtrace *mtrace)
{
	char src_str[INET_ADDRSTRLEN];
	char dst_str[INET_ADDRSTRLEN];
	char grp_str[INET_ADDRSTRLEN];

	printf("* Mtrace from %s to %s via group %s\n",
	       inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	       inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	       inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
}

static int recv_response(int fd, int *hops, struct igmp_mtrace *mtracer)
{
	int recvd;
	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	struct ip *ip;
	struct igmp_mtrace *mtrace;
	int mtrace_len;
	int responses;
	u_short sum;

	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);

	if (recvd < 1) {
		fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
		return -1;
	}

	if (recvd < (int)sizeof(struct ip)) {
		fprintf(stderr, "no ip header\n");
		return -1;
	}

	ip = (struct ip *)mtrace_buf;

	if (ip->ip_v != 4) {
		fprintf(stderr, "IP not version 4\n");
		return -1;
	}

	sum = ip->ip_sum;
	ip->ip_sum = 0;

	if (sum != in_cksum(ip, ip->ip_hl * 4))
		return -1;

	mtrace = (struct igmp_mtrace *)(mtrace_buf + (4 * ip->ip_hl));

	mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4;

	if (mtrace_len < (int)MTRACE_HDR_SIZE)
		return -1;

	sum = mtrace->checksum;
	mtrace->checksum = 0;
	if (sum != in_cksum(mtrace, mtrace_len)) {
		fprintf(stderr, "mtrace checksum wrong\n");
		return -1;
	}

	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
		return -1;


	responses = mtrace_len - sizeof(struct igmp_mtrace);
	responses /= sizeof(struct igmp_mtrace_rsp);

	if (responses > MTRACE_MAX_HOPS) {
		fprintf(stderr, "mtrace too large\n");
		return -1;
	}

	if (hops)
		*hops = responses;

	if (mtracer)
		memcpy(mtracer, mtrace, mtrace_len);

	return 0;
}

static int wait_for_response(int fd, int *hops, struct igmp_mtrace *mtrace,
			     long *ret_msec)
{
	fd_set readfds;
	struct timeval timeout;
	int ret = -1;
	long msec, rmsec, tmsec;

	FD_ZERO(&readfds);
	FD_SET(fd, &readfds);

	memset(&timeout, 0, sizeof(timeout));

	timeout.tv_sec = MTRACE_TIMEOUT;

	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	do {
		ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
		if (ret <= 0)
			return ret;
		rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
		msec = tmsec - rmsec;
	} while (recv_response(fd, hops, mtrace) != 0);

	if (ret_msec)
		*ret_msec = msec;

	return ret;
}

static bool check_end(struct igmp_mtrace *mtrace, int hops)
{
	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
}

int main(int argc, char *const argv[])
{
	struct in_addr mc_source;
	struct in_addr iface_addr;
	struct in_addr gw_addr;
	struct in_addr mtrace_addr;
	struct igmp_mtrace mtrace;
	struct igmp_mtrace *mtracep;
	int hops = 255;
	int rhops;
	int maxhops = 255;
	int perhop = 3;
	int ifindex;
	int unicast = 1;
	int ttl = 64;
	int fd = -1;
	int ret = -1;
	int c;
	long msec;
	int i, j;
	char ifname[IF_NAMESIZE];
	char mbuf[MTRACE_BUF_LEN];

	mtrace_addr.s_addr = inet_addr("224.0.1.32");

	uid_t uid = getuid();

	if (uid != 0) {
		printf("must run as root\n");
		exit(EXIT_FAILURE);
	}

	if (argc <= 0)
		progname = "mtracebis";
	else
		progname = argv[0];

	if (argc != 2) {
		usage();
		exit(EXIT_FAILURE);
	}

	while (1) {
		static struct option long_options[] = {
			{"help", no_argument, 0, 'h'},
			{"version", no_argument, 0, 'v'},
			{0, 0, 0, 0}};
		int option_index = 0;

		c = getopt_long(argc, argv, "vh", long_options, &option_index);

		if (c == -1)
			break;

		switch (c) {
		case 'h':
			usage();
			exit(0);
		case 'v':
			version();
			exit(0);
		default:
			usage();
			exit(EXIT_FAILURE);
		}
	}
	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
		usage();
		fprintf(stderr, "%s: %s not a valid IPv4 address\n", argv[0],
			argv[1]);
		exit(EXIT_FAILURE);
	}

	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	if (ifindex < 0) {
		fprintf(stderr, "%s: failed to get route to source %s\n",
			argv[0], argv[1]);
		exit(EXIT_FAILURE);
	}

	if (if_indextoname(ifindex, ifname) == NULL) {
		fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
			strerror(errno));
		exit(EXIT_FAILURE);
	}

	/* zero mtrace struct */
	memset((char *)&mtrace, 0, sizeof(mtrace));

	/* set up query */
	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	mtrace.hops = hops;
	mtrace.checksum = 0;
	mtrace.grp_addr.s_addr = 0;
	mtrace.src_addr = mc_source;
	mtrace.dst_addr = iface_addr;
	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	mtrace.rsp_ttl = ttl;
	mtrace.qry_id = 0xffffff & time(NULL);

	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));

	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);

	if (fd < 1) {
		fprintf(stderr, "%s: socket error: %s\n", argv[0],
			strerror(errno));
		exit(EXIT_FAILURE);
	}

	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
			 strlen(ifname));

	if (ret < 0) {
		fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}

	print_query(&mtrace);
	if (send_query(fd, gw_addr, &mtrace) < 0) {
		fprintf(stderr, "%s: sendto error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}
	printf("Querying full reverse path...\n");
	mtracep = (struct igmp_mtrace *)mbuf;
	ret = wait_for_response(fd, &rhops, mtracep, &msec);
	if (ret > 0) {
		print_responses(mtracep, rhops, msec);
		ret = 0;
		goto close_fd;
	}
	if (ret < 0) {
		fprintf(stderr, "%s: select error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}
	printf(" * ");
	printf("switching to hop-by-hop:\n");
	print_dest(&mtrace);
	for (i = 1; i < maxhops; i++) {
		print_line_no(i);
		mtrace.hops = i;
		for (j = 0; j < perhop; j++) {
			mtrace.qry_id++;
			mtrace.checksum = 0;
			mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
			if (send_query(fd, gw_addr, &mtrace) < 0) {
				fprintf(stderr, "%s: sendto error: %s\n",
					argv[0], strerror(errno));
				ret = EXIT_FAILURE;
				goto close_fd;
			}
			ret = wait_for_response(fd, &rhops, mtracep, &msec);
			if (ret > 0) {
				if (check_end(mtracep, rhops)) {
					print_rsp(&mtracep->rsp[rhops - 1]);
					print_summary(mtracep, rhops, msec);
					ret = 0;
					goto close_fd;
				}
				if (i > rhops) {
					printf(" * ...giving up.\n");
					ret = 0;
					goto close_fd;
				}
				print_rsp(&mtracep->rsp[rhops - 1]);
				break;
			}
			printf(" *");
		}
		if (ret <= 0)
			printf("\n");
	}
	ret = 0;
close_fd:
	close(fd);
	exit(ret);
}

#else /* __linux__ */

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
	printf("%s implemented only for GNU/Linux\n", argv[0]);
	exit(0);
}

#endif /* __linux__ */
Commit	Line	Data
4d9ad5dc MS	1	/*
	2	* Multicast Traceroute for FRRouting
	3	* Copyright (C) 2018 Mladen Sablic
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along
	16	* with this program; see the file COPYING; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18	*/
	19
	20	#ifdef __linux__
	21
	22	#include "pim_igmp_mtrace.h"
	23
	24	#include "checksum.h"
	25	#include "mtracebis_routeget.h"
	26
	27	#include <sys/select.h>
	28	#include <netinet/in.h>
	29	#include <arpa/inet.h>
	30	#include <unistd.h>
	31	#include <sys/types.h>
	32	#include <sys/time.h>
	33	#include <stdio.h>
	34	#include <stdlib.h>
	35	#include <string.h>
	36	#include <time.h>
	37	#include <net/if.h>
5b02bd3a DS	38	#include <unistd.h>
5b02bd3a DS	39	#include <getopt.h>
04a2eef3	40	#include <netdb.h>
4d9ad5dc MS	41
	42	#define MTRACEBIS_VERSION "0.1"
	43	#define MTRACE_TIMEOUT (5)
	44
	45	#define IP_HDR_LEN (sizeof(struct ip))
	46	#define IP_RA_LEN (4)
	47	#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
	48	#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)
	49
	50	static const char *progname;
	51	static void usage(void)
	52	{
	53	fprintf(stderr, "Usage : %s <multicast source>\n", progname);
	54	}
	55	static void version(void)
	56	{
	57	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
	58	}
	59
04a2eef3 MS	60	static void print_host(struct in_addr addr)
	61	{
	62	struct hostent *h;
	63
	64	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	65	if (h == NULL)
	66	printf("?");
	67	else
	68	printf("%s", h->h_name);
	69	printf(" (%s) ", inet_ntoa(addr));
	70	}
	71
	72	static void print_line_no(int i)
	73	{
	74	printf("%3d ", -i);
	75	}
	76
	77	static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
	78	{
	79	static char buf[80];
	80
	81	buf[0] = '\0';
	82
	83	switch (proto) {
	84	case MTRACE_RTG_PROTO_DVMRP:
	85	return "DVMRP";
	86	case MTRACE_RTG_PROTO_MOSPF:
	87	return "MOSPF";
	88	case MTRACE_RTG_PROTO_PIM:
	89	return "PIM";
	90	case MTRACE_RTG_PROTO_CBT:
	91	return "CBT";
	92	case MTRACE_RTG_PROTO_PIM_SPECIAL:
	93	return "PIM special";
	94	case MTRACE_RTG_PROTO_PIM_STATIC:
	95	return "PIM static";
	96	case MTRACE_RTG_PROTO_DVMRP_STATIC:
	97	return "DVMRP static";
	98	case MTRACE_RTG_PROTO_PIM_MBGP:
	99	return "PIM MBGP";
	100	case MTRACE_RTG_PROTO_CBT_SPECIAL:
	101	return "CBT special";
	102	case MTRACE_RTG_PROTO_CBT_STATIC:
	103	return "CBT static";
	104	case MTRACE_RTG_PROTO_PIM_ASSERT:
	105	return "PIM assert";
	106	default:
	107	sprintf(buf, "unknown protocol (%d)", proto);
	108	return buf;
	109	}
	110	}
	111
	112	static void print_rtg_proto(uint32_t rtg_proto)
	113	{
	114	printf("%s", rtg_proto_str(rtg_proto));
	115	}
	116
	117	static void print_fwd_ttl(uint32_t fwd_ttl)
	118	{
	119	printf("thresh^ %d", fwd_ttl);
	120	}
	121
	122	static const char *fwd_code_str(enum mtrace_fwd_code code)
	123	{
124	static char buf[80];
125
126	buf[0] = '\0';
127
128	switch (code) {
129	case MTRACE_FWD_CODE_NO_ERROR:
130	return "no error";
131	case MTRACE_FWD_CODE_WRONG_IF:
132	return "wrong interface";
133	case MTRACE_FWD_CODE_PRUNE_SENT:
134	return "prune sent";
135	case MTRACE_FWD_CODE_PRUNE_RCVD:
136	return "prune received";
137	case MTRACE_FWD_CODE_SCOPED:
138	return "scoped";
139	case MTRACE_FWD_CODE_NO_ROUTE:
140	return "no route";
141	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
142	return "wrong last hop";
143	case MTRACE_FWD_CODE_NOT_FORWARDING:
144	return "not forwarding";
145	case MTRACE_FWD_CODE_REACHED_RP:
146	return "reached RP";
147	case MTRACE_FWD_CODE_RPF_IF:
148	return "RPF interface";
149	case MTRACE_FWD_CODE_NO_MULTICAST:
150	return "no multicast";
151	case MTRACE_FWD_CODE_INFO_HIDDEN:
152	return "info hidden";
153	case MTRACE_FWD_CODE_NO_SPACE:
154	return "no space";
155	case MTRACE_FWD_CODE_OLD_ROUTER:
156	return "old router";
157	case MTRACE_FWD_CODE_ADMIN_PROHIB:
158	return "admin. prohib.";
159	default:
160	sprintf(buf, "unknown fwd. code (%d)", code);
161	return buf;
162	}
163	}
164
165	static void print_fwd_code(uint32_t fwd_code)
166	{
167	printf("%s", fwd_code_str(fwd_code));
168	}
169
170	static void print_rsp(struct igmp_mtrace_rsp *rsp)
171	{
172	print_host(rsp->outgoing);
173	if (rsp->fwd_code == 0) {
174	print_rtg_proto(rsp->rtg_proto);
175	printf(" ");
176	print_fwd_ttl(rsp->fwd_ttl);
177	} else {
178	print_fwd_code(rsp->fwd_code);
179	}
180	printf("\n");
181	}
182
183	static void print_dest(struct igmp_mtrace *mtrace)
184	{
185	print_line_no(0);
186	print_host(mtrace->dst_addr);
187	printf("\n");
188	}
189
190	static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
191	{
192	int i;
193	int t = 0;
194
195	for (i = 0; i < hops; i++)
196	t += mtrace->rsp[i].fwd_ttl;
197
198	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
199	}
200
201	static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
202	{
203	int i;
204
205	print_dest(mtrace);
206
207	for (i = 0; i < hops; i++) {
208	print_line_no(i + 1);
209	print_rsp(&mtrace->rsp[i]);
210	}
211	print_summary(mtrace, hops, msec);
212	}
213
4d9ad5dc MS	214	static int send_query(int fd, struct in_addr to_addr,
	215	struct igmp_mtrace *mtrace)
	216	{
	217	struct sockaddr_in to;
	218	socklen_t tolen;
	219	int sent;
	220
	221	memset(&to, 0, sizeof(to));
	222	to.sin_family = AF_INET;
	223	to.sin_addr = to_addr;
	224	tolen = sizeof(to);
	225
	226	sent = sendto(fd, (char )mtrace, sizeof(mtrace), MSG_DONTWAIT,
	227	(struct sockaddr *)&to, tolen);
	228
	229	if (sent < 1)
	230	return -1;
	231	return 0;
	232	}
	233
	234	static void print_query(struct igmp_mtrace *mtrace)
	235	{
	236	char src_str[INET_ADDRSTRLEN];
	237	char dst_str[INET_ADDRSTRLEN];
	238	char grp_str[INET_ADDRSTRLEN];
	239
	240	printf("* Mtrace from %s to %s via group %s\n",
	241	inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	242	inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	243	inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
	244	}
	245
04a2eef3	246	static int recv_response(int fd, int hops, struct igmp_mtrace mtracer)
4d9ad5dc MS	247	{
	248	int recvd;
	249	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	250	struct ip *ip;
	251	struct igmp_mtrace *mtrace;
	252	int mtrace_len;
	253	int responses;
4d9ad5dc MS	254	u_short sum;
	255
	256	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);
	257
	258	if (recvd < 1) {
	259	fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
	260	return -1;
	261	}
	262
	263	if (recvd < (int)sizeof(struct ip)) {
	264	fprintf(stderr, "no ip header\n");
	265	return -1;
	266	}
	267
	268	ip = (struct ip *)mtrace_buf;
	269
	270	if (ip->ip_v != 4) {
	271	fprintf(stderr, "IP not version 4\n");
	272	return -1;
	273	}
	274
	275	sum = ip->ip_sum;
	276	ip->ip_sum = 0;
	277
	278	if (sum != in_cksum(ip, ip->ip_hl * 4))
	279	return -1;
	280
	281	mtrace = (struct igmp_mtrace )(mtrace_buf + (4 ip->ip_hl));
	282
	283	mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4;
	284
	285	if (mtrace_len < (int)MTRACE_HDR_SIZE)
	286	return -1;
	287
	288	sum = mtrace->checksum;
	289	mtrace->checksum = 0;
	290	if (sum != in_cksum(mtrace, mtrace_len)) {
	291	fprintf(stderr, "mtrace checksum wrong\n");
	292	return -1;
	293	}
	294
	295	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
	296	return -1;
	297
	298
	299	responses = mtrace_len - sizeof(struct igmp_mtrace);
	300	responses /= sizeof(struct igmp_mtrace_rsp);
	301
04a2eef3 MS	302	if (responses > MTRACE_MAX_HOPS) {
	303	fprintf(stderr, "mtrace too large\n");
	304	return -1;
	305	}
4d9ad5dc MS	306
	307	if (hops)
	308	*hops = responses;
	309
04a2eef3 MS	310	if (mtracer)
04a2eef3 MS	311	memcpy(mtracer, mtrace, mtrace_len);
4d9ad5dc MS	312
	313	return 0;
	314	}
	315
04a2eef3 MS	316	static int wait_for_response(int fd, int hops, struct igmp_mtrace mtrace,
04a2eef3 MS	317	long *ret_msec)
4d9ad5dc MS	318	{
	319	fd_set readfds;
	320	struct timeval timeout;
	321	int ret = -1;
	322	long msec, rmsec, tmsec;
	323
	324	FD_ZERO(&readfds);
	325	FD_SET(fd, &readfds);
	326
	327	memset(&timeout, 0, sizeof(timeout));
	328
	329	timeout.tv_sec = MTRACE_TIMEOUT;
	330
	331	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	332	do {
	333	ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
	334	if (ret <= 0)
	335	return ret;
	336	rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	337	msec = tmsec - rmsec;
04a2eef3 MS	338	} while (recv_response(fd, hops, mtrace) != 0);
	339
	340	if (ret_msec)
	341	*ret_msec = msec;
4d9ad5dc MS	342
	343	return ret;
	344	}
	345
04a2eef3 MS	346	static bool check_end(struct igmp_mtrace *mtrace, int hops)
	347	{
	348	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
	349	}
	350
4d9ad5dc MS	351	int main(int argc, char *const argv[])
	352	{
	353	struct in_addr mc_source;
	354	struct in_addr iface_addr;
	355	struct in_addr gw_addr;
	356	struct in_addr mtrace_addr;
	357	struct igmp_mtrace mtrace;
04a2eef3	358	struct igmp_mtrace *mtracep;
4d9ad5dc MS	359	int hops = 255;
	360	int rhops;
	361	int maxhops = 255;
	362	int perhop = 3;
	363	int ifindex;
	364	int unicast = 1;
	365	int ttl = 64;
	366	int fd = -1;
	367	int ret = -1;
	368	int c;
04a2eef3	369	long msec;
4d9ad5dc MS	370	int i, j;
4d9ad5dc MS	371	char ifname[IF_NAMESIZE];
04a2eef3	372	char mbuf[MTRACE_BUF_LEN];
4d9ad5dc MS	373
	374	mtrace_addr.s_addr = inet_addr("224.0.1.32");
	375
	376	uid_t uid = getuid();
	377
	378	if (uid != 0) {
	379	printf("must run as root\n");
	380	exit(EXIT_FAILURE);
	381	}
	382
	383	if (argc <= 0)
	384	progname = "mtracebis";
	385	else
	386	progname = argv[0];
	387
	388	if (argc != 2) {
	389	usage();
	390	exit(EXIT_FAILURE);
	391	}
	392
	393	while (1) {
	394	static struct option long_options[] = {
	395	{"help", no_argument, 0, 'h'},
	396	{"version", no_argument, 0, 'v'},
996c9314	397	{0, 0, 0, 0}};
4d9ad5dc MS	398	int option_index = 0;
	399
	400	c = getopt_long(argc, argv, "vh", long_options, &option_index);
	401
	402	if (c == -1)
	403	break;
	404
	405	switch (c) {
	406	case 'h':
	407	usage();
	408	exit(0);
	409	case 'v':
	410	version();
	411	exit(0);
	412	default:
	413	usage();
	414	exit(EXIT_FAILURE);
	415	}
	416	}
	417	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
	418	usage();
	419	fprintf(stderr, "%s: %s not a valid IPv4 address\n", argv[0],
	420	argv[1]);
	421	exit(EXIT_FAILURE);
	422	}
	423
	424	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	425	if (ifindex < 0) {
	426	fprintf(stderr, "%s: failed to get route to source %s\n",
	427	argv[0], argv[1]);
	428	exit(EXIT_FAILURE);
	429	}
	430
	431	if (if_indextoname(ifindex, ifname) == NULL) {
	432	fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
	433	strerror(errno));
	434	exit(EXIT_FAILURE);
	435	}
	436
	437	/* zero mtrace struct */
	438	memset((char *)&mtrace, 0, sizeof(mtrace));
	439
	440	/* set up query */
	441	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	442	mtrace.hops = hops;
	443	mtrace.checksum = 0;
	444	mtrace.grp_addr.s_addr = 0;
	445	mtrace.src_addr = mc_source;
	446	mtrace.dst_addr = iface_addr;
	447	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	448	mtrace.rsp_ttl = ttl;
	449	mtrace.qry_id = 0xffffff & time(NULL);
	450
	451	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	452
	453	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
	454
	455	if (fd < 1) {
	456	fprintf(stderr, "%s: socket error: %s\n", argv[0],
	457	strerror(errno));
	458	exit(EXIT_FAILURE);
	459	}
	460
	461	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
462	strlen(ifname));
463
464	if (ret < 0) {
465	fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
466	strerror(errno));
467	ret = EXIT_FAILURE;
468	goto close_fd;
469	}
470
471	print_query(&mtrace);
472	if (send_query(fd, gw_addr, &mtrace) < 0) {
473	fprintf(stderr, "%s: sendto error: %s\n", argv[0],
474	strerror(errno));
475	ret = EXIT_FAILURE;
476	goto close_fd;
477	}
478	printf("Querying full reverse path...\n");
04a2eef3 MS	479	mtracep = (struct igmp_mtrace *)mbuf;
04a2eef3 MS	480	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	481	if (ret > 0) {
04a2eef3	482	print_responses(mtracep, rhops, msec);
4d9ad5dc MS	483	ret = 0;
	484	goto close_fd;
	485	}
	486	if (ret < 0) {
	487	fprintf(stderr, "%s: select error: %s\n", argv[0],
	488	strerror(errno));
	489	ret = EXIT_FAILURE;
	490	goto close_fd;
	491	}
	492	printf(" * ");
	493	printf("switching to hop-by-hop:\n");
04a2eef3	494	print_dest(&mtrace);
4d9ad5dc	495	for (i = 1; i < maxhops; i++) {
04a2eef3	496	print_line_no(i);
4d9ad5dc MS	497	mtrace.hops = i;
	498	for (j = 0; j < perhop; j++) {
	499	mtrace.qry_id++;
	500	mtrace.checksum = 0;
	501	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	502	if (send_query(fd, gw_addr, &mtrace) < 0) {
	503	fprintf(stderr, "%s: sendto error: %s\n",
	504	argv[0], strerror(errno));
	505	ret = EXIT_FAILURE;
	506	goto close_fd;
	507	}
04a2eef3	508	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	509	if (ret > 0) {
04a2eef3 MS	510	if (check_end(mtracep, rhops)) {
	511	print_rsp(&mtracep->rsp[rhops - 1]);
	512	print_summary(mtracep, rhops, msec);
	513	ret = 0;
	514	goto close_fd;
	515	}
4d9ad5dc	516	if (i > rhops) {
04a2eef3	517	printf(" * ...giving up.\n");
4d9ad5dc MS	518	ret = 0;
	519	goto close_fd;
	520	}
04a2eef3	521	print_rsp(&mtracep->rsp[rhops - 1]);
4d9ad5dc MS	522	break;
	523	}
	524	printf(" *");
	525	}
	526	if (ret <= 0)
	527	printf("\n");
	528	}
	529	ret = 0;
	530	close_fd:
	531	close(fd);
	532	exit(ret);
	533	}
	534
	535	#else /* __linux__ */
	536
	537	#include <stdio.h>
	538	#include <stdlib.h>
	539
	540	int main(int argc, char *argv[])
	541	{
	542	printf("%s implemented only for GNU/Linux\n", argv[0]);
	543	exit(0);
	544	}
	545
	546	#endif /* __linux__ */